Tankless water heater for mixed use

I am looking for some pros and cons for the purchase of a tankless water heater that will in the future be used for hydronic or radiant heat as well. We will need it to supply a shower, washing machine and heat simultaneously.
The popular brands in my N. Cal. region are Takagi and Noritz. Many plumbing contractors around here install Takagi but I don't know why.
Thanks.

heat

Radiant and hydronic are the same thing, but the heater demands and temperatures are different, as is the domestic use temperature, so you either need individual units or a means of controlling the various temperatures for efficiency and safety